For vehicles and in particular for sport utility type vehicles (SUV's), it is desirable to be able to move a mirror head which holds the mirror with respect to a mounting bracket on the vehicle away from or back towards the mounting bracket. This enables the mirror head to be positioned either close to the side of the motor vehicle, or to be extended away from the motor vehicle. In its extended position, an increased (wider) useful field of view behind the vehicle is provided. This is important where the rear view may be obstructed by a load on the vehicle or a trailer that is being towed for instance.
Various powered telescoping external vehicle mirrors have been developed. For larger mirrors twin telescopic arms are commonly used. With some designs, the twin arms each comprise a hollow outer arm and an inner arm. The hollow outer arm is connected to the bracket and the inner arm is connected to the mirror head. By making the outer arm hollow, a light weight yet strong construction can be achieved.
In order to keep the mirror head compact and to take advantage of the internal space defined by the hollow outer arms, drive components and stabilising components are advantageously mounted on the inner arm for action against the inside of the outer arm. A difficulty with this design arises in coordination of the drive of the two arms to ensure that skewing and jamming does not occur. Where a single drive motor is employed, a further difficulty arises in transferring the output of a single drive motor to drive components within the inner arms.
Two designs developed by the applicant formed the subject of earlier filed International Patent Application Nos. PCT/AU00/00077 and PCT/AU02/01237. In the first of those patent applications, a system employing cables extending from the head into the arm is disclosed. In the second patent application, a flexible toothed belt extends from the head into the arm.
It is an object of the present invention to provide an improved and simplified power telescoping vehicle external mirror assembly that overcomes at least some of the above problems.